MOM to reach Mars with zero fuel

Isro has planned four mid-course corrections to precisely steer MOM to Mars

Indian Space Research Organisation (Isro) has said the Mars Orbiter Mission (MOM) will cover 680 million km with no fuel. The velocity required by MOM to reach Mars had already been imparted during the Trans-Mars Injection.

Now, MOM is cruising with a velocity of 32.8 km/second. MOM is expected to reach Mars in September 2014.

MOM doesn’t require any fuel to travel from Earth to Mars in its Mars-Transfer Trajectory. However, a little fuel was required to correct the trajectory and control the orientation of the spacecraft, Isro said.

On December 11, Isro will conduct the first small mid-course correction maneuver. The subsequent ones will be carried out in April and August next year. “In line with our fetish for jargon, the fancy term coined for these operations is trajectory correction maneuver (TCM)!” Isro said.

To precisely steer MOM to Mars, Isro has planned four mid-course corrections, using the 22 N thrusters on board. On the mode of disposal of the Mars orbiter at the end of the mission, Isro said the spacecraft was built according to the planetary protection implementation requirements specified for ‘orbiter’ category of missions.

When MOM travelled in a tangent to the Earth’s orbit around the Sun, a component of the Earth’s velocity was added to MOM’s escape velocity.

The MOM propulsion system uses monomethyl hydrazine as fuel and dinitrogen tetroxide as oxidiser.

On November 5, Isro had successfully launched the mission from the Sriharikotta space station near Chennai. On December 1, it successfully conducted a critical maneuver to place the Mars orbiter spacecraft in the Mars transfer trajectory.

Isro said the shortest distance between Mars and Earth was 54.6 million km. At a later stage, deceleration to match the planet’s speed would require an extremely large amount of fuel. The route that requires the least amount of fuel is an elliptical orbit, which forms a tangent to Mars’s and Earth’s orbit around the Sun. MOM is travelling a distance of about 680 million km in this elliptical trajectory.